Credentials consist of data that can be used to prove of ownership of privilege, role, rights, etc. (i.e., an assertion) and generally include or are constructed a secret, policy information, event parameters, a value or identity assertion and/or an authentication function that binds the secret and the parameters with the assertion. Example credentials include PKI certificates and the corresponding private keys, such as X.509 certificates and associated private keys. Other example credentials are HID iCLASS, One Time Passwords based on Symmetric Keys, or simply a password and an account identifier. Since the secret part of the credential needs protection, the secret part of the credentials may be located in a secure element. UICC, SIM, MicroSDs, and Embedded Hardware Security modules are examples of Secure elements provided, for example, on a mobile phone.
A credential may be revoked if the assertion corresponding to the credential is no longer true. For example, if a user leaves an organization, then a user's credentials that allow physical access to the facilities of the organization may need to be revoked. There are a number of mechanisms for revoking credentials, including, for example, disabling use of a credential associated to a mobile phone at a credential verification back office or by requesting the credential issuer to set the credential status to revoked and then publishing the credential status. Known credential revocation techniques may be relatively slow, expensive and not very scalable and may adversely impact credential verification systems. For example, X.509 certificate revocation systems require the publication and distribution of certificate revocation lists (CRLs) from the credential issuer, or the use of certificate status responders, both of which may be inherently time delayed so that, depending on the frequency of revocation and the time it takes to distribute the CRLs, there may some time in which the credential can still be used after the credential has been revoked.
It is desirable to provide a system that addresses shortcomings of known credential revocation systems.